The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 16, 1991
Filed:
Mar. 17, 1989
John M Dahlen, Duxbury, MA (US);
Narender K Chhabra, Bedford, MA (US);
Richard K Araujo, Tewksbury, MA (US);
James R Scholten, Sudbury, MA (US);
Robert W Reid, Acton, MA (US);
Matti Soikkeli, Braintree, MA (US);
The Charles Stark Draper Laboratory, Cambridge, MA (US);
Abstract
A low-cost floating drifter adapted to accurately follow near-surface ocean currents and transmit periodically to monitoring satellites data and position-determining information. Global tracking of ocean currents is made economically and scientifically feasible by the use of large numbers of such drifters. The drifter includes a floating surface buoy in the approximate shape of an oblate spheroid and containing an electronic system, a slotted plane antenna, transmitter, sunrise and sunset detector, environmental sensors, buoy hull strain sensor and battery power supply. The surface buoy is stabilized and induced to follow ocean currents by a drogue suspended from the bottom center surface. The drogue includes a wire-cored buoyant rope of up to hundreds of meters in length and weighted to a slight negative buoyancy. The drogue may also include an elongated cylindrical sock of substantially greater diameter than the rope. By means of the sunrise and sunset detector and the electronic system, the transmitter is controlled to operate only during selected passes of a solar synchronous satellite so as to conserve the battery and permit unattended life of up to several years. By means of the hull strain sensor and the electronic system the transmitted signal contains data from which the drogue integrity can be determined. Other status and environmental data are also transmitted. The drifter has special provisions to resist corrosion, fish-bite damage and biological fouling.